Rotational two-dimensional (2D) X-ray angiographic images provide valuable geometric information on vascular structures for diagnoses of various vascular diseases, such as coronary artery diseases and cerebral diseases. After a contrast agent (usually an x-ray opaque material, such as iodine) is injected into the vessel, the image contrast of the vessel regions is generally enhanced. Three-dimensional (3D) vascular tree reconstruction using the 2D projection images is often beneficial to reveal the true 3D measurements, including diameters, curvatures and lengths, of various vessel segments of interests, for further functional assessments of the targeted vascular regions.
Extant 3D reconstruction methods typically rely on 2D vessel structures segmented from multiple X-ray images from different imaging projection angles (such as a primary angle and a secondary angle). Usually, 2D vessel centerlines are first extracted from the segmented vessel regions, and 3D centerlines are then computed by establishing the proper projection imaging system geometry. One technical challenge presented by extant methods is the foreshortening issue. The vessel lengths are slightly different when viewed from different angles due to the nature of the projection imaging, causing foreshortening. Generally, foreshortening may be reduced by avoiding using images containing pronounced foreshortening vessel segments (represented with darker intensity) for 3D reconstruction. However, at least some level of foreshortening frequently occurs due to the curved geometrical nature of vessels and due to physiological motion of the patient during the imaging process (e.g., due to respiratory motion and cardiac motion).
Embodiments of the disclosure address the above problems by systems and methods for improved three-dimensional blood vessel reconstructions using angiographic images.